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1.
Lipase-catalyzed acidolysis of perilla oil with caprylic acid to produce structured lipids 总被引:6,自引:0,他引:6
In-Hwan Kim Hakryul Kim Ki-Teak Lee Soo-Hyun Chung Soon-Nam Ko 《Journal of the American Oil Chemists' Society》2002,79(4):363-367
Structured lipids were synthesized by acidolysis of perilla oil and caprylic acid using two lipases, Lipozyme RM IM from Rhizomucor miehei and Lipozyme TL IM from Thermomyces lanuginosa. Effects of molar ratio, reaction time, reaction temperature, enzyme load, and solvent content on acidolysis reactions were
studied. The solvent content ranged from 0.0 (solvent-free) to 85.3%. The results showed that the incorporation increased
in parallel with solvent content to 49.0% with Lipozyme RM IM and to 63.8% with Lipozyme TL IM. After 24 h incubation in n-hexane, caprylic acids were incorporated to 48.5 mol% with Lipozyme RM IM and to 51.4 mol% with Lipozyme TL IM, respectively,
whereas linolenic acid content was reduced from 61.4 to 31.5 mol% with Lipozyme RM IM and to 28.4 mol% with Lipozyme TL IM,
respectively. Lipozyme TL IM showed a higher acyl migration rate than Lipozyme RM IM when acidolysis was performed in the
reaction system containing n-hexane as a solvent, whereas the difference in acyl migration between the two lipases in the solvent-free system was negligible. 相似文献
2.
Production of margarine fats by enzymatic interesterification with silica-granulated Thermomyces lanuginosa lipase in a large-scale study 总被引:5,自引:5,他引:0
Hong Zhang Xuebing Xu Jörgen Nilsson Huiling Mu Jens Adler-Nissen Carl-Erik Høy 《Journal of the American Oil Chemists' Society》2001,78(1):57-64
Interesterification of a blend of palm stearin and coconut oil (75∶25, w/w), catalyzed by an immobilized Thermomyces lanuginosa lipase by silica granulation, Lipozyme TL IM, was studied for production of margarine fats in a 1- or 300-kg pilot-scale
batch-stirred tank reactor. Parameters and reusability were investigated. The comparison was carried out between enzymatic
and chemical interesterified products. Experimentally, Lipozyme TL IM had similar activity to Lipozyme IM for the interesterification
of the blend. Within the range of 55–80°C, temperature had little influence on the degree of interesterification for 6-h reaction,
but it had slight impact on the content of free fatty acids (FFA). Drying of Lipozyme TL IM from water content 6 to 3% did
not affect its activity, whereas it greatly reduced FFA and diacylglycerol contents in the products. Lipozyme TL IM was stable
in the 1-kg scale reactor at least for 11 batches and the 300-kg pilot-scale reactor at least for nine batches. Due to regiospecificity
of the lipase (sn-1,3 specific), enzymatically interesterified products had different fatty acid distribution at sn-2 position from the chemically randomized products, implying the potential nutritional benefits of the new technology.
Presented at the 91st American Oil Chemists' Society Annual Meeting in San Diego, April 28, 2000. 相似文献
3.
Carlos F. Torres Farida Munir C. Otero Charles G. Hill Jr. 《Journal of the American Oil Chemists' Society》2002,79(8):775-781
Thermomyces lanuginosa lipase was employed to catalyze the interesterification reaction between corn oil and tristearin at 45°C in a solvent-free
system. HPLC and GC analyses were used to monitor both the distribution of TAG and the concentrations of MAG, DAG, and TAG
as the reaction progressed. The positional distribution of the FA residues in the interesterified product was also determined
for comparison to that of the original corn oil. Two different weight ratios of corn oil to tristearin were studied. Addition
of molecular sieves to the reaction medium reduced the percentage of hydrolysis from 15 to 7. In order to improve the results
obtained with Lipozyme TL IM, an immobilization of T. lanuginosa lipase was carried out. At a solids loading of 10% (w/w), the new immobilized lipase reduced the concentration of tristearin
from 6 to 0.5% in only 30 min. 相似文献
4.
Lipase-catalyzed interesterification between fish oil and medium-chain TAG has been investigated in a packedbed reactor with
a commercially immobilized enzyme. The enzyme, a Thermomyces lanuginosa lipase immobilized on silica by granulation (lipozyme TL IM; Novozymes A/S, Bagsvaerd, Denmark), has recently been developed
for fat modification. This study focuses on the new characteristics of the lipase in a packed-bed reactor when applied to
interesterification of TAG. The degree of reaction was strongly related to the flow rate (residence time) and temperature,
whereas formation of hydrolysis by-products (DAG and FFA) were only slightly affected by reaction conditions. The degree of
reaction reached equilibrium at 30–40 min residence time, and the most suitable temperature was 60°C or higher with respect
to the maximal degree of reaction. The lipase was stable in a 2-wk continuous operation without adjustment of water content
or activity of the column and the substrate mixture. 相似文献
5.
Tiago Simões Francisco Valero Carla Tecelão Suzana Ferreira-Dias 《Journal of the American Oil Chemists' Society》2014,91(3):411-419
This study aims to produce human milk fat substitutes by an acidolysis reaction between lard and the free fatty acids (FFA) from a fish oil concentrate rich in docosahexaenoic acid, in solvent-free media. The immobilized commercial lipases from (1) Rhizomucor miehei (Lipozyme RM IM), (2) Thermomyces lanuginosa (Lipozyme TL IM) and (3) Candida antarctica (Novozym 435) were tested as biocatalyst. Also, the heterologous Rhizopus oryzae lipase (rROL), immobilized in Accurel® MP 1000, was tested as a feasible alternative to the commercial lipases. After 24 h of reaction at 50 °C, similar incorporations of polyunsaturated fatty acids (c.a. 17 mol%) were attained with Novozym 435, Lipozyme RM IM and rROL. The lowest incorporation was achieved with Lipozyme TL IM (7.2 mol%). Modeling acidolysis catalyzed by rROL and optimization of reaction conditions were performed by response surface methodology, as a function of the molar ratio FFA/lard and the temperature. The highest acidolysis activity was achieved at 40 °C at a molar ratio of 3:1, decreasing with both temperature and molar ratio. Operational stability studies for rROL in seven consecutive 24-h batches were carried out. After the fourth batch, the biocatalyst retained about 55 % of the original activity (half-life of 112 h). 相似文献
6.
Enzymatic Interesterification of Palm Stearin and Coconut Oil by a Dual Lipase System 总被引:1,自引:0,他引:1
Nuzul A. Ibrahim Zheng Guo Xuebing Xu 《Journal of the American Oil Chemists' Society》2008,85(1):37-45
Enzymatic interesterification of palm stearin with coconut oil was conducted by applying a dual lipase system in comparison
with individual lipase-catalyzed reactions. The results indicated that a synergistic effect occurred for many lipase combinations,
but largely depending on the lipase species mixed and their ratios. The combination of Lipozyme TL IM and RM IM was found
to generate a positive synergistic action at all test mixing ratios. Only equivalent amount mixtures of Lipozyme TL IM with
Novozym 435 or Lipozyme RM IM with Novozym 435 produced a significant synergistic effect as well as the enhanced degree of
interesterification. The interesterification catalyzed by Lipozyme TL IM mixed with thermally inactivated immobilized lipase
preparations indicated that the carrier property may play an important role in affecting the interaction of two mixed lipases
and the subsequent reactions. A dual enzyme system, consisting of immobilized lipases and a non-immobilized one (Lipase AK),
in most cases apparently endows the free lipase with a considerably enhanced activity. 70% Lipase AK mixed with 30% immobilized
lipase (Lipozyme TL IM, RM IM and Novozym 435) can achieve an increase in activity greater than 100% over the theoretical
value when the reaction proceeds for 2 h. The co-immobilization action of the carrier of the immobilized lipases towards the
free lipase was proposed as being one of the reasons leading to the synergistic effect and this has been experimentally verified
by a reaction catalyzed by a Lipase AK-inactivated preparation. No apparently synergistic effect of the combinations of Lipozyme
TL IM and RM IM was observed when the dual enzyme systems applied to the continuous reaction performed in a packed bed reactor.
In brief, this work demonstrated the possibility of increasing the reaction rate or enhancing the degree of conversion by
employing a dual lipase system as a biocatalyst. 相似文献
7.
The triglyceride (fatty acid) selectivity of an immobilized lipase from Thermomyces lanuginosa (Lipozyme TL IM) was investigated in lipase-catalyzed interesterification reactions between two nono-acid TG in n-hexane. Tristearin (tri-C18∶0) was used as a reference in a series of TG with saturated FA from tri-C4∶0 to tri-C20∶0, except
for tri-C6∶0, and in a series of unsaturated FA from tri-C18∶1 to tri-C18∶3. The quantification was performed by HPLC, and
different methods of selectivity evaluation were used. None of the methods used showed any significant differences between
the performances of the lipase on the different TG, indicating that Lipozyme TL IM is nonselective toward FA or TG in the
system used. A response surface design was used to investigate the influence of water activities (a
w
) and reaction temperatures on the reactivity of Lipozyme TL IM with a system of tripalmitin (tri-C16∶0) and trilaurin (tri-C12∶0)
in n-hexane. An increase in temperature (40 to 60°C) was found to affect the reactivity of the lipase significantly. The reactivity
of Lipozyme TL IM was unaffected by the change in a
w
from 0.1130 to 0.5289. An increase in a
w
only led to an increase in FFA formation. 相似文献
8.
In-Hwan Kim Chil-Surk Yoon Soo-Hee Cho Kwang-Won Lee Soo-Hyun Chung Beom-Seok Tae 《Journal of the American Oil Chemists' Society》2001,78(5):547-551
Three commercially available immobilized lipases, Novozym 435 from Candida antarctica, Lipozyme IM from Rhizomucor miehei, and Lipase PS-C from Pseudomonas cepacia, were used as biocatalysts for the interesterification of conjugated linoleic acid (CLA) ethyl ester and tricaprylin. The
reactions were carried out in hexane, and the products were analyzed by gas-liquid chromatography. The effects of molar ratio,
enzyme load, incubation time, and temperature on CLA incorporation were investigated. Novozym 435, as compared to Lipozyme
IM and Lipase PC-C, showed the highest degree of CLA incorporation into tricaprylin. By hydrolysis with pancreatic lipase,
it was found that Lipozyme IM and Lipase PS-C exhibited high selectivity for the sn-1,3 position of the triacylglycerol early in the interesterification, with small extents of incorporation of CLA into the
sn-2 position, probably due to acyl migration, at later reaction times. A small extent of sn-1,3 selectivity during interesterification by Novozym 435 was observed. 相似文献
9.
Ihsan Karabulut Gokhan Durmaz Ali Adnan Hayaloglu 《Journal of the American Oil Chemists' Society》2010,87(11):1301-1307
The C18 unsaturated fatty acid (UFA) selectivity of three immobilized lipases, namely, Lipozyme TL IM from Thermomyces lanuginosa, Lipozyme RM IM from Rhizomucor miehei, and Novozym 435 from Candida antarctica, was determined in acidolysis conducted in hexane. Tripalmitin with a mixture of equimolar quantities of C18 UFAs was used
as the substrate. Significantly different incorporation rates were observed for C18 UFAs used (p < 0.05). The highest incorporation was obtained for all three C18 UFAs with Novozym 435 followed by Lipozyme RM IM and Lipozyme
TL IM catalyzed acidolysis under default conditions (substrate mole ratio 1:1; temperature 50 °C; reaction time 6 h; enzyme
dosage 10%). Incorporation of the equimolar quantities of C18 UFAs was in the order C18:3 > C18:2 > C18:1 which also reflects
C18 UFAs preferences of the lipases. The effects of operating variables on incorporation or UFA selectivity of lipases were
also investigated. Among the experimental parameters including the mole ratio of fatty acid to triolein, temperature, enzyme
dosage, and time on incorporation, the effect of the substrate mole ratio on UFA selectivity was greater than those of the
others. 相似文献
10.
Mohamed M. Soumanou Uwe T. Bornscheuer 《European Journal of Lipid Science and Technology》2003,105(11):656-660
Fatty acid alkyl esters were produced from various vegetable oils by transesterification with different alcohols using immobilized lipases. Using n‐hexane as organic solvent, all immobilized lipases tested were found to be active during methanolysis. Highest conversion (97%) was observed with Thermomyces lanuginosa lipase after 24 h. In contrast, this lipase was almost inactive in a solvent‐free reaction medium using methanol or 2‐propanol as alcohol substrates. This could be overcome by a three‐step addition of methanol, which works efficiently for a range of vegetable oils (e.g. cottonseed, peanut, sunflower, palm olein, coconut and palm kernel) using immobilized lipases from Pseudomonas fluorescens (AK lipase) and Rhizomucor miehei (RM lipase). Repeated batch reactions showed that Rhizomucor miehei lipase was very stable over 120 h. AK and RM lipases also showed acceptable conversion levels for cottonseed oil with ethanol, 1‐propanol, 1‐butanol and isobutanol (50‐65% conversion after 24 h) in solvent‐free conditions. Methyl and isopropyl fatty acid esters obtained by enzymatic alcoholysis of natural vegetable oils can find application in biodiesel fuels and cosmetics industry, respectively. 相似文献
11.
The possibilities of producing structured phospholipids between soybean phospholipids and caprylic acid by lipase-catalyzed
acidolysis were examined in continuous packedbed enzyme reactors. Acidolysis reactions were performed in both a solvent system
and a solvent-free system with the commercially immobilized lipase from Thermomyces lanuginosa (Lipozyme TL IM) as catalyst. In the packed bed reactors, different parameters for the lipase-catalyzed acidolysis were elucidated,
such as solvent ratio (solvent system), temperature, substrate ratio, residence time, water content, and operation stability.
The water content was observed to be very crucial for the acidolysis reaction in packed bed reactors. If no water was added
to the substrate during reactions under the solvent-free system, very low incorporation corporation of caprylic acid was observed.
In both solvent and solvent-free systems, acyl incorporation was favored by a high substrate ratio between acyl donor and
phospholipids, a longer residence time, and a higher reaction temperature. Under certain conditions, the incorporation of
around 30% caprylic acid can be obtained in continuous operation with hexane as the solvent.
Presented at the 95th American Oil Chemists' Society Annual Meeting and Expo in Cincinnati, Ohio, May 10, 2004. 相似文献
12.
Carlos F. Torres Farida Munir Louis P. Lessard Charles G. Hill Jr. 《Journal of the American Oil Chemists' Society》2002,79(7):655-661
Solvent-free acidolysis of tristearin with CLA has been carried out in a packed-bed reactor. An immobilized lipase from Thermomyces lanuginosa (Lipozyme TL IM) was employed as the biocatalyst. Elevated temperatures (75°C) were utilized to eliminate solid substrates.
The reaction kinetics were modeled by using a rate equation of the general Michaelis-Menten form. Both the extent of incorporation
of CLA and the extent to which FFA were released were investigated. Positional analysis of the purified TAG obtained after
a pseudo space time of 0.6 h indicated that CLA was preferentially incorporated at the sn-1,3 positions of the glycerol backbone, although 10% of the sn-2 positions were occupied by CLA residues. At a pseudo space time of 0.6 h, 38% of the initial CLA was incorporated in acylglycerols;
the associated extent of hydrolysis was 8.3%. 相似文献
13.
Lipase-catalyzed incorporation of n−3 PUFA into palm oil 总被引:4,自引:0,他引:4
Two immobilized lipases, IM60 from Rhizomucor miehei and QLM from Alcaligenes sp., were used as biocatalysts for the modification of the FA composition of palm oil by incorporating n−3 PUFA. Acidolysis
and interesterification reactions were conducted with hexane as organic solvent, and the products were analyzed by using GLC.
After a 24-h incubation in hexane, there was an average incorporation of 20.8% EPA and 15.6% DHA into palm oil, respectively,
while the percentages of palmitic and oleic acids in palm oil decreased by 28.8 and 11.8%, respectively. Higher EPA and DHA
incorporation was obtained when EPAX (fish oil concentrate high in n−3 PUFA) was used in the ethyl ester form (interesterification
reaction) than in the free acid form (acidolysis) in the presence of Lipozyme (IM60 lipase. Lipase QLM was found to discriminate
against EPA, and it showed slightly better catalytic activity for DHA in the free acid form than in the ethyl ester form.
Generally, as the mole ratio of the acyl donor to TAG increased, the percentage incorporation of EPA and DHA increased; however,
reactions catalyzed by Lipozyme IM60 did not show increases in the incorporation beyond a TAG/EPAX mole ratio of 3. When limitations
due to mass transfer were not a factor, an increase in the reactant amount also gave an increase in the percentage incorporation
of the n−3 PUFA. Palm oil containing EPA and DHA was successfully produced and may be beneficial in certain food and nutritional
applications. 相似文献
14.
Manuel Criado Estela Hernández‐Martín Cristina Otero 《European Journal of Lipid Science and Technology》2007,109(5):474-485
The lipase‐catalyzed interesterification of virgin olive oil and fully hydrogenated palm oil (FHPO) was studied in a batch reactor operating at 75 °C. The reactions between olive oil {rich in OOO (32.36%), OPO (21.7%) and OLO (11.6%) [L = linoleic; O = oleic; P = palmitic acid]} and the fully hydrogenated fat {(36.5% PSP, 28.8% PPP, 23.2% SPS) [S = stearic acid]} produced semi‐solid fats. For an initial weight ratio of olive oil to FHPO of 60 : 40, the reaction product is a complex mixture of triacylglycerol (TAG) species. The TAG profile of the fat product is time dependent. Because of the high viscosity of the liquid reagent phase, it was important to determine if mass transfer effects were significant. Hence, the reaction was optimized with respect to the type and speed of agitation employed, temperature, use of solvent, and the type of biocatalyst. Three immobilized lipases [from Thermomyces lanuginosus (TL IM), Rhizomucor miehei (RM IM) and Candida antarctica B (Novozym 435)] were compared as catalysts for the interesterification reaction. Equilibrium is reached four times faster (in 1–4 h) with a magnetic stirrer to provide agitation than when agitation is not sufficient, i.e. when orbital agitation is employed. Equilibrium was reached faster with Lipozyme TL IM than with the other two lipases. The effects of all the factors investigated on the composition of the products have also been determined. Semi‐solid fats obtained with the non‐specific Novozym 435 contain levels of unsaturated fatty acid residues on sn‐2 sites that are similar to the products obtained with the 1(3)‐regiospecific enzymes Lipozyme TL IM and RM IM. The chemical properties of the product semi‐solid fat were characterized. The fat prepared using optimal reaction conditions contained 17.20% OPO, 13.61% OOO, 11.09% POP, and 10.35% OSP isomers as the primary products. The induction time obtained in the assay of the oxidative stability of the fat product was 21 h at 98 °C. The lipases Lipozyme TL IM and Novozym 435 were very stable with residual activities of 90 and 100%, respectively, after 15 batch reaction cycles. 相似文献
15.
Structured lipids resembling human milk fat and containing GLA were synthesized by an enzymatic interesterification between tripalmitin, hazelnut oil FA, and GLA in n-hexane. Commercially immobilized 1,3-specific lipases, lipozyme® RM IM and Lipozyme® TL IM, were used as the biocatalysts. The effect of these enzymes on the incorporation levels was investigated. A central composite design with five levels and three factors—substrate ratio, reaction temperature, and time—were used to model and optimize the reaction conditions via response surface methodology. Good quadratic models were obtained for the incorporation of GLA (response 1) and oleic acid (response 2) by multiple regression and backward elimination. The determination coefficient (R 2) values for the models were found to be 0.92 and 0.94 for the reactions catalyzed by Lipozyme RM IM, and 0.92 and 0.88 for the reactions catalyzed by Lipozyme TL IM, respecitively. The optimal conditions generated from the models for the targeted GLA (10%) and oleic acid (45%) incorporation were 14.8 mol/mol, 55°C, and 24 h; 14 mol/mol, 55°C, and 24 h for substrate ratio (moles total FA/mol tripalmitin), temperature and time for the reactions catalyzed by Lipozyme RM IM and Lipozyme TL IM, respectively. Human milk fat substitutes containing GLA that can be included in infant formulas were success-fully produced using both Lipozyme RM IM and Lipozyme TL IM enzymes. The effect of the two enzymes on the incorporation of GLA and oleic acid were found to be similar. 相似文献
16.
Natlia M. Osrio M. Manuela R. da Fonseca Suzana Ferreira‐Dias 《European Journal of Lipid Science and Technology》2006,108(7):545-553
The operational stability of a commercial immobilized lipase from Thermomyces lanuginosa (“Lipozyme TL IM”) during the interesterification of two fat blends, in solvent‐free media, in a continuous packed‐bed reactor, was investigated. Blend A was a mixture of palm stearin (POS), palm kernel oil (PK) and sunflower oil (55 : 25 : 20, wt‐%) and blend B was formed by POS, PK and a concentrate of triacylglycerols rich in n‐3 polyunsaturated fatty acids (PUFA) (55 : 35 : 10, wt‐%). The bioreactor operated continuously at 70 °C, for 580 h (blend A) and 390 h (blend B), at a residence time of 15 min. Biocatalyst activity was evaluated in terms of the decrease of the solid fat content at 35 °C of the blends, which is a key parameter in margarine manufacture. The inactivation profile of the biocatalyst could be well described by the first‐order deactivation model: Half‐lives of 135 h and 77 h were estimated when fat blends A and B, respectively, were used. Higher levels of PUFA in blend B, which are rather prone to oxidation, may explain the lower lipase stability when this mixture was used. The free fatty acid content of the interesterified blends decreased to about 1% during the first day of operation, remaining constant thereafter. 相似文献
17.
Monjur Hossen Ernesto Hernandez 《European Journal of Lipid Science and Technology》2005,107(10):730-736
Structured phospholipids were synthesized with the functional lipid conjugated linoleic acid (CLA). The lipase‐ and phospholipase A2‐catalyzed enzymatic acidolysis reaction between phospholipids (PL) and CLA was used for fatty acid modification. Enzymatic processes were an effective way to produce structured PL. Screening of four lipases and immobilized phospholipase A2 and a combination of lipase and phospholipase showed that only Lipozyme RM IM and Lipozyme TL IM were effective in incorporation of CLA into PL. The maximum incorporation achieved by the latter enzyme was 16% with soy PL in 72 h. 相似文献
18.
Ana Sofia Pires Natália M. Osório Ana Cláudia Nascimento Frederik van Keulen M. Manuela R. da Fonseca Suzana Ferreira‐Dias 《European Journal of Lipid Science and Technology》2008,110(10):893-904
The feasibility to discriminate among samples of different fat blends prior and after inorganic or lipase‐catalyzed interesterification, via pattern recognition techniques [principal component analysis (PCA) and discriminant analysis (DA)], was investigated. Blends I and II, consisting of mixtures of palm stearin, palm kernel oil and a concentrate of triacylglycerols (TAG) rich in n‐3 polyunsaturated fatty acids (EPAX 4510TG or EPAX 2050TG) were used. These blends, prior (64 samples) and after interesterification, catalyzed by an immobilized Thermomyces lanuginosa lipase (Lipozyme TL IM, 54 samples) or by sodium methoxide (10 samples), were characterized by their acylglycerol profiles (25 chromatographic peaks) and solid fat content (SFC) at 10, 20, 30 and 35 °C. PCA on the multivariate data (i) showed that the initial samples were characterized by higher SFC and higher contents of high‐melting TAG and (ii) suggested two separate clusters of initial and interesterified samples. DA was performed on the multivariate data to determine which of the 29 variables have discriminative power. When the 124 samples, characterized by their acylglycerols, were grouped into (i) initial and interesterified samples of blends I or II (four groups) or (ii) also by the catalyst used (six groups), 98.4% of the samples were correctly classified. 相似文献
19.
Synthesis of Fatty Acid Ethyl Ester from Acid Oil in a Continuous Reactor via an Enzymatic Transesterification
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Nakyung Choi Yangha Kim Jeom-Sig Lee Jieun Kwak Junsoo Lee In-Hwan Kim 《Journal of the American Oil Chemists' Society》2016,93(3):311-318
Synthesis of a fatty acid ethyl ester via the lipase‐catalyzed transesterification of acid oil and ethanol was investigated in a continuous reactor. Lipozyme TL IM was employed as the immobilized lipase. This immobilized lipase derived from Thermomyces lanuginosus was purchased from Novozymes (Seoul, Korea). The acid oil was prepared by the acidification of soapstock formed as a by‐product during the refining of rice bran oil. The parameters investigated were water content, temperature, and molar ratio of substrates. The relative activity of Lipozyme TL IM was assessed during the repeated use of the immobilized lipase. The water content of the substrate had a considerable effect on the yield and the optimum water content was 4 %. The optimum temperature and molar ratio of acid oil to ethanol were 20 °C and 1:4, respectively. The maximum yield of approximately 92 % was achieved under the optimum conditions. The corresponding compositions were 92 % fatty acid ethyl esters, 3 % fatty acids, and 5 % acylglycerols. When glycerol formed during the reaction was removed by intermittent washing with ethanol, the relative activity of lipase was maintained over 82 % for a total usage of 27 cycles. For a mean residence time of 4 h, the half‐life times of Lipozyme TL IM on the control (unwashed) and treatment (washed) were 39 and 45 cycles, respectively. 相似文献
20.
Sirirung Wongsakul Uwe T. Bornscheuer Aran H‐Kittikun 《European Journal of Lipid Science and Technology》2004,106(10):665-670
Two approaches on enzymatic phospholipid modification were studied: (1) transphosphatidylation of the 1,2‐dilauroyl‐sn‐glycero‐3‐phosphocholine (DLPC) and ethanolamine in biphasic and anhydrous organic solvent systems by phospholipase D (PLD) and (2) incorporation of oleic acid into the sn1‐position of DLPC in organic solvents with different immobilized lipases at controlled water activity. First, DLPC was chemically synthesized from glycerophosphocholine and lauric acid. Next, PLD‐catalyzed head group exchange of DLPC with ethanolamine was studied using an enzyme from Streptomyces antibioticus expressed recombinantly in E. coli. A comparison of the free PLD with the biocatalyst activated by a salt‐activation technique using KCl showed that the salt‐activated enzyme (PLD‐KCl) was 10–12 folds more active based on the amount of protein used. Thus, DLPC was quantitatively converted to 1,2‐dilauroyl‐sn‐glycero‐3‐phosphoethanolamine in an anhydrous solvent system within 12 h at 60 °C. For the acidolysis of DLPC with oleic acid, among the four lipases studied (CAL‐B, Lipozyme TL IM, Lipozyme RM IM and lipase D immobilized on Accurel EP‐100), Lipozyme TL IM showed the highest activity and incorporation of oleic acid. A quantitative incorporation was achieved at 40 °C using a 8‐fold molar excess of oleic acid in n‐hexane at a water activity of 0.11. 相似文献